Global Illumination

What is Global Illumination in Unity?

Global Illumination (GI) is a fancy name for a system that models indirect lighting - light that has bounced from one surface onto another.

No GI - Direct Light Only - Direct Light with GI
Light bouncing onto interior columns
No GI - Direct Light Only - Direct Light with GI
Light bouncing through corridors

GI allows you to light a large area with just a single light source.

GI from a single sunlight
GI from a directional light
GI from a single point light
GI from a single point light

Notes